import java.util.ArrayList;

public class Test2 {
    public static void main(String[] args) {
        String s1 = "welcome to bit";
        String s2 = "come";
        ArrayList<Character> arrayList = new ArrayList();
        for (int i = 0; i < s1.length(); i++) {
            char ch = s1.charAt(i);
            if(!s2.contains(ch+"")){
               arrayList.add(ch);
            }
        }
        for (Character ch:arrayList) {
            System.out.print(ch);
        }
    }
}
